Recently, improving fuel efficiency has been one of the major issues in the vehicle industry. Because depletion of natural resources is expected, such improvement in fuel efficiency can be one of the best ways for energy conservation. Hence, efforts on reduction in vehicle weight have been extensively made to improve fuel efficiency.
Particularly, decreasing thickness of product made of plastics among vehicle parts has been suggested for reducing vehicle weight. However, decreased thickness of product may cause deterioration in moldability at the time of injection molding and deterioration in physical properties, such as stiffness and impact strength, as the thickness of such plastic products is reduced to be a thin film.
Meanwhile, a certain polypropylene resin composition having excellent stiffness and high impact property has been reported previously. The impact property may be secured by adding a rubber component excellent in impact improvement effect to a high crystalline homopolypropylene excellent in stiffness, and further the stiffness may be reinforced by adding an inorganic filler. This polypropylene resin composition, however, may not satisfy the stiffness and impact resistance required for a vehicle interior part and the thickness of the part may be reduced. See Korean Patent Application Publication No. 2010-0027922.
Hence, because a polypropylene resin composition is utilized for a vehicle interior material, development for such a polypropylene resin composition, of which the excellent physical properties such as high stiffness and high impact property are preserved while the moldability is improved even though the thickness of product is thinned or to be thin film and which is further suitable for a vehicle interior material, is strongly desired.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.